[Stefan Buda]

Now that you provided some numbers, it is much easier to answer your question.

In a nutshell, yes the larger setup would produce better results in some respects but not all.

As you said, the field of view would be the same. The required exposure for extended objects would also be the same. The main advantage would be in resolving fine detail in nebula and the stars will be smaller relative to the larger pixels. That is a big advantage if you are going after a globular cluster, but not big if you are chasing the Running Man nebula.

EDIT: I got it wrong. Exposure time would be the same if you used the same sensor, but with the scaled up sensor the bigger scope would be better at catching up with the Running Man nebula too.